Coca-Cola has come under fire after a private investigation accused it of "serious infringement" of the rights of its dispatched workers in China.

"These employees are involved in the most dangerous, intense and tiresome labor, work the longest hours, but receive the lowest wage and face arrears with and even cutbacks on their pay," said a 28-page report written by seven university students after a month of participatory research and released in Beijing on Sunday.

They collected the information between July and August while working in Coca-Cola's bottlers in Guangzhou, Dongguan and Huizhou in Guangdong province, as well as the company's suppliers in Shanghai and Hangzhou in Zhejiang province.

They claimed they collected the information from fellow dispatched workers.

A significant body of dispatched labor and other non-contracted workers exists in the company's China branch, their report said.

It accused the company of exploiting the workers - some of whom worked more than 100 hours of overtime per month, above the 36 hour maximum stipulated by law - paid them the minimum wage and gave them few rights.

Dispatched workers are employed by agencies, which send them to fill "temporary, supporting or replaceable positions", according to Clause 66 of the Labor Contract Law.

Zhai Mei, associate external affairs director of Coca-Cola China, said yesterday the company is "pretty confident" of dealing with the problem.

"The students never came into direct contact with us, and their research may not have been comprehensive," she said.

In a statement released last night, Coca-Cola China denied the report's claims, saying the company and its bottlers not only "strictly comply with the laws and regulations regarding labor practices", but also "have strict supplier guiding principles" for vendors and suppliers.